Implementation and Initial Evaluation of Craniospinal Irradiation Using Volumetric Modulated Arc Therapy: A Dosimetric, Clinical and Operational Analysis

Background: As an elementary radiotherapy treatment, cranial irradiation (CSI) is used to combat cancers that typically spread to the meninges, especially medulloblastoma. Using two-dimensional (2D) or three-dimensional conformal radiotherapy (3D-CRT) for conventional delivery is problematic because the doses aren't always the same. Volumetric modulated arc treatment (VMAT) could be an evolution that leads to more predictable and long-lasting work rhythm performances. 

Objective: The goal of this study is to investigate at the full clinical utilisation of a multi-isocenter VMAT approach for CSI. It will examine at its dosimetric quality, acute toxicity profile, and operational implications in a real-life radiotherapy department. 

Methods: We conducted a retrospective cohort study on all patients (both children and adults) who experienced definitive or adjuvant VMAT-based CSI at our institution from January 2023 to November 2025. We studied at the dosimetric factors for OARs and target areas comprised the whole brain, spinal canal, and cribriform plate. CTCAE v5.0 was used to grade acute effects once a week. We compiled operational measures, such as planning time, procedure execution time, and quality assurance (QA) score rates, and compared them to 3D-CRT statistics from earlier years. 

Results The results demonstrated that VMAT-CSI had greater target coverage (mean PTV V95% = 98.2% ± 1.1%) and dose consistency (uniformity Index = 0.08 ± 0.02) than 3D-CRT. It was conceivable to conserve an enormous amount of OAR. The standard doses to the cochleae and heart were cut by 15% and 20%, respectively. The short-term side effects were minor and mostly consisted of tiredness (65%) and dermatitis (40%). Grade 3 leukopenia occurred in approximately 15% of patients, mostly those who received additional chemotherapy. In regard to how it executes, treatment delivery time declined from about 25 minutes (3D-CRT) to 8–10 minutes (VMAT), and patient-specific QA showed high repeatability (average Gamma pass rate 97.5%, 3%/3mm).

Conclusion: Therefore, using multi-isocenter VMAT for CSI is achievable and is an improvement over present approaches in terms of dosimetry and operating efficiency. It has an appealing initial safety profile, but long-term follow-up is necessary for understanding how it impacts people subsequently on. VMAT-CSI is the reliable recognised standard for neuroaxis irradiation today.